There are other reputable sources.
Clifton is a major league animal rights kook.
"Around the world, societies that practice animal husbandry are desensitized societies. The abuse of animals inevitably spills over into the treatment of women and children. Polygamy, forced marriage, female genital mutilation, and slavery persist in ... as extensions of common agricultural practice to those of our own species who are least able to protect themselves."
Link
There are many critques of Clifton's "study" and methodology available.
KC DOG BLOG is good start. Google will reveal others.
For good investigation and analysis look to the CDC which is up front about its methodological weaknesses.
Its conclusion for example...
"Although fatal attacks on humans appear to be a breed-specific problem (pit bull-type dogs and Rottweilers), other breeds may bite and cause fatalities at higher rates. Because of difficulties inherent in determining a dog’s breed with certainty, enforcement of breed-specific ordinances raises constitutional and practical issues. Fatal attacks represent a small proportion of dog bite injuries to humans and, therefore, should not be the primary factor driving public policy concerning dangerous dogs. Many practical alternatives to breed-specific ordinances exist and hold promise for prevention of dog bites. (J Am Vet Med Assoc 2000;217:836–840)"
(What they are touching on here is the numerator/denominator problem. For accurate study and conclusions both the numerator[the # of dogs of a specific breed involved in attacks] and the denominator [the total population of the specific breed] must be known.)
Karen Delise also does an honest job beginning with her book Fatal Dog Attacks: The Stories Behind the Statistics
and followed by The Pit Bull Placebo which she has made available online.
Her organization, The National Canine Research Council strives for accurate information, for example, their 2009 study of dog bite-related fatalities....
"NCRC is the only organization that does not rely on media sources for information on dog bite-related fatalities.
There were 31 dog bite-related fatalities in 2009. NCRC contacted officials on each case in order to obtain the most accurate and comprehensive information available. We have re-interviewed sources that the media has reached, and located others that they have not, among whom may be police investigators, animal control officers, coroners, veterinarians, health department officials, dog owners, and eye witnesses. We have obtained incident reports, bite reports, human and animal autopsy reports, summaries of judicial proceedings, and crime scene data and photographs.
Official reports often do not agree with news accounts and/or contain important information that was either unavailable or not of interest to reporters. The NCRC 2009 final report on dog bite-related fatalities is released at the end of 2010 because we believe that our mission of preserving the human-canine bond obligates us to be as accurate about these emotionally charged incidents as we can, so that they are calmly, correctly and, therefore, usefully understood.
Accuracy takes time, work and research."
Investigative Reports on Dog Bite-Related Fatalities for 2009